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 #include &quot;model.h&quot;
 #include &lt;QIcon&gt;
 #include &lt;QPixmap&gt;

 Model::Model(int rows, int columns, QObject *parent)
     : QAbstractItemModel(parent),
       rc(rows), cc(columns),
       tree(new QVector&lt;Node&gt;(rows, Node(0)))
 {

 }

 Model::~Model()
 {
     delete tree;
 }

 QModelIndex Model::index(int row, int column, const QModelIndex &amp;parent) const
 {
     if (row &lt; rc &amp;&amp; row &gt;= 0 &amp;&amp; column &lt; cc &amp;&amp; column &gt;= 0) {
         Node *p = static_cast&lt;Node*&gt;(parent.internalPointer());
         Node *n = node(row, p);
         if (n)
             return createIndex(row, column, n);
     }
     return QModelIndex();
 }

 QModelIndex Model::parent(const QModelIndex &amp;child) const
 {
     if (child.isValid()) {
         Node *n = static_cast&lt;Node*&gt;(child.internalPointer());
         Node *p = parent(n);
         if (p)
             return createIndex(row(p), 0, p);
     }
     return QModelIndex();
 }

 int Model::rowCount(const QModelIndex &amp;parent) const
 {
     return (parent.isValid() &amp;&amp; parent.column() != 0) ? 0 : rc;
 }

 int Model::columnCount(const QModelIndex &amp;parent) const
 {
     Q_UNUSED(parent);
     return cc;
 }

 QVariant Model::data(const QModelIndex &amp;index, int role) const
 {
     if (!index.isValid())
         return QVariant();
     if (role == Qt::DisplayRole)
         return &quot;Item &quot; + QString::number(index.row()) + &quot;:&quot; + QString::number(index.column());
     if (role == Qt::DecorationRole) {
         if (index.column() == 0)
             return iconProvider.icon(QFileIconProvider::Folder);
         return iconProvider.icon(QFileIconProvider::File);
     }
     return QVariant();
 }

 QVariant Model::headerData(int section, Qt::Orientation orientation, int role) const
 {
     static QIcon services(QPixmap(&quot;:/images/services.png&quot;));
     if (role == Qt::DisplayRole)
         return QString::number(section);
     if (role == Qt::DecorationRole)
         return qVariantFromValue(services);
     return QAbstractItemModel::headerData(section, orientation, role);
 }

 bool Model::hasChildren(const QModelIndex &amp;parent) const
 {
     if (parent.isValid() &amp;&amp; parent.column() != 0)
         return false;
     return rc &gt; 0 &amp;&amp; cc &gt; 0;
 }

 Qt::ItemFlags Model::flags(const QModelIndex &amp;index) const
 {
     if (!index.isValid())
         return 0;
     return (Qt::ItemIsDragEnabled|Qt::ItemIsSelectable|Qt::ItemIsEnabled);
 }

 Model::Node *Model::node(int row, Node *parent) const
 {
     if (parent &amp;&amp; !parent-&gt;children)
         parent-&gt;children = new QVector&lt;Node&gt;(rc, Node(parent));
     QVector&lt;Node&gt; *v = parent ? parent-&gt;children : tree;
     return const_cast&lt;Node*&gt;(&amp;(v-&gt;at(row)));
 }

 Model::Node *Model::parent(Node *child) const
 {
     return child ? child-&gt;parent : 0;
 }

 int Model::row(Node *node) const
 {
      const Node *first = node-&gt;parent ? &amp;(node-&gt;parent-&gt;children-&gt;at(0)) : &amp;(tree-&gt;at(0));
      return (node - first);
 }</pre>
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